U.S. Pat. No. 6,820,576 discloses a vehicle including an engine and a generator disposed outwardly of the engine and driven by the engine. The generator includes a rotating shaft aligned with a crankshaft of the engine, thereby resulting in an increase in the width of the vehicle in a left-to-right direction and a reduction in the strength of the crankshaft or the rotating shaft. Furthermore, since the generator supplies electricity to electrical appliances in the vehicle only during idle running of the engine, fuel will be consumed seriously.